Sheet feeding device

ABSTRACT

Imaging target media stacked in a tray are bent in a width direction orthogonal to a transmission direction so that rigidity of the imaging target media in the transmission direction increases than the rigidity before bending. Consequently, even though a separation imaging-target medium is bound together with a transportation imaging-target medium using a binding member, the separation imaging-target medium is transmitted to an imaging unit along with the transportation imaging-target medium by transporting rollers without bending in the transmission direction. A superimposed-transmission of the imaging target media is detected by sensors and rotation of the transmitting roller is stopped. Due to this, the superimposed-transmission of the imaging target media is stopped just before the imaging unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet feeding device that transportssheet-type imaging target media to imaging units that are set in animage scanner or an image copier.

2. Description of the Related Art

A sheet feeding device, in other words, a so-called auto document feeder(ADF) is suggested that transports originals (sheet-type imaging targetmedia) one by one to imaging units that are set in an image scanner oran image copier.

In such a sheet feeding device, among the originals stacked in a tray,transportation originals that touch a transmitting roller aresequentially transmitted to the imaging units due to rotation of thetransmitting roller. When a separation original is stacked on thetransportation originals, a separation unit of a separating roller etc.touches the separation original and separates the separation originalfrom the transportation originals by moving the separation original in adirection opposite to the transportation originals, which aretransmitted in a transmission direction by the transmitting roller. Dueto this, the originals are transported one by one to the imaging units.

When the transportation original and the separation original are boundtogether by a binding member such as a stapler at a front end of thetransmission direction, and if the transportation original and theseparation original are transmitted together to the imaging units due toa rotational force of the transmitting roller, a torque sensor detectscurrent fluctuations of a direct current (DC) motor, in other words,detects load torque fluctuations of the DC motor that rotatably drivesthe transmitting roller. Thus, a bulk-transmission orsuperposed-transmission of the originals is detected androtation-driving of the transmitting roller is stopped. Due to this,transportation of the originals by the transmitting roller isdiscontinued.

However, when the transportation original and the separation originalare bound together by the binding member such as a stapler at a rear endof the transmission direction, the transportation original istransported to the imaging units by the transmitting roller, while theseparation original is separated from the transportation original by theseparating unit of the separating roller etc. Due to this, theseparation original undergoes bending, ultimately a binding component ofthe binding member between the transportation original and theseparation original ruptures, and a jam of originals occurs.

To overcome such a problem, before the binding component between thetransportation original and the separation original ruptures and the jamof originals occurs, it is necessary to stop the rotation-driving of thetransmitting roller and discontinue the transportation of the originals.

In the sheet feeding device disclosed in Japanese Patent No. 3197029,when the transportation original and the separation original are boundtogether by the binding member such as a stapler at the rear end of thetransmission direction, and when the separation original, which isseparated by the separating roller from the transportation original thatis transported to the imaging unit, undergoes bending, the rotation ofthe transmitting roller is stopped.

However, in the sheet feeding device disclosed above, a dedicated sensorthat detects bending of the separation original needs to be set. Thus,an electrical configuration of the device becomes complicated and costof the device increases.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

An aspect of the present invention, a sheet feeding device includes atray in which sheet-type imaging target media are stacked; atransmitting roller that rotates and transmits, upon touching a singleimaging target medium that is to be transported among the stackedimaging target media, the touched transportation imaging-target mediumto an imaging unit; a separating unit that touches, among the stackedimaging target media, a separation imaging-target medium that is not tobe transported, separates the separation imaging-target medium by movingthe separation imaging-target medium in a direction opposite to thetransportation imaging-target medium that is transmitted to the imagingunit by the transmitting roller, and prevents transmission of theseparation imaging-target medium to the imaging unit; a rotatablydriving unit that rotatably drives the transmitting roller; atransporting roller that rotates and transports, upon touching thetransportation imaging-target medium transmitted by the transmittingroller, the touched transportation imaging-target medium to an imagingposition of the imaging target medium formed by the imaging unit; adetecting sensor that is set between the transmitting roller and thetransporting roller and that detects whether the imaging target mediatransmitted by the transmitting roller are only the transportationimaging-target media; and a controlling unit that stops, upondetermining that the detected imaging target media include the imagingtarget media other than the transportation imaging-target media,rotation of at least the transmitting roller via the rotatably drivingunit, wherein the tray includes a bending unit that bends the stackedimaging target media from a rear to a front end of a transmissiondirection, in a direction that intersects the transmission direction ofthe imaging target media by the transmitting roller and reduces a degreeof bending of the imaging target media from the rear end to the frontend of the transmission direction.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an outline of a sheet feeding deviceaccording to a first embodiment of the present invention;

FIG. 2 is a perspective view of a bending unit of a tray of the sheetfeeding device;

FIG. 3 is a perspective view of a relation between the bending unit andan imaging target medium placed in the bending unit;

FIG. 4 is a perspective view of a relation between the bending unit anda plurality of imaging target media stacked in the bending unit;

FIGS. 5A and 5B are perspective views of an outline of detectingsensors;

FIG. 6 is a flowchart of operations of an image scanner to which thesheet feeding device according to the first embodiment is applied;

FIGS. 7A and 7B are perspective views of a bending unit of a tray of asheet feeding device according to a second embodiment of the presentinvention;

FIG. 8 is a perspective view of a bending unit of a tray of a sheetfeeding device according to a third embodiment of the present invention;

FIG. 9 is a perspective view of a relation between a pressing member anda bending unit of a tray of a sheet feeding device according to a fourthembodiment of the present invention;

FIG. 10 is a side view of a modification example of the pressing member;

FIG. 11 is a perspective view of a status when a thick imaging targetmedium is placed in the tray;

FIG. 12 is a side view of a pressing member of a sheet feeding deviceaccording to a fifth embodiment of the present invention; and

FIG. 13 is a side view of a pressing member of a sheet feeding deviceaccording to a sixth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the sheet feeding device according to thepresent invention are explained below with reference to the accompanyingdrawings. However, the present invention is not to be thus limited tothe embodiments described further. Although the sheet feeding deviceaccording to the present invention is set to an image scanner, the sheetfeeding device can be set, for example, to an image copier etc.

A sheet feeding device according to a first embodiment of the presentinvention is explained below. FIG. 1 is a typical sectional view of anoutline of the sheet feeding device according to the first embodiment.

A sheet feeding device 10 includes a tray 12, a transmitting roller 14,a separating roller 16 as a separating unit, a motor 18 as a rotatablydriving unit, a pair of transporting rollers 20, a pair of detectingsensors 22, and a control circuit 24 as a controlling unit.

Sheet-type imaging target media P are stacked in the tray 12. As shownin FIG. 2, the tray 12 includes a bending unit 26.

As shown in FIG. 3, apart from bending the imaging target medium P,which is stacked in the tray 12, from a rear end to a front end of atransmission direction of the imaging target medium P by thetransmitting roller 14, in a direction that intersects the transmissiondirection, the bending unit 26 also reduces a degree of bending of theimaging target medium P from the rear end to the front end of thetransmission direction. As shown in FIG. 2, in the first embodiment, thebending unit 26 includes a foundation member 26 a facing the imagingtarget medium P stacked in the tray 12 and a pair of bending members 26b set on the foundation member 26 a on both edges of a width direction,which is orthogonal to the transmission direction.

The foundation member 26 a is in the form of a rectangular board.

Further, each bending member 26 b is positioned on the foundation member26 a and a bottom of each bending member 26 b is integrated with thefoundation member 26 a. However, each bending member 26 b can bedetachably positioned on the foundation member 26 a to enable insertionand separation of each bending member 26 b to and from the foundationmember 26 a. Further, the bending members 26 b are formed as triangularpillars and a length of the bending members 26 b in the transmissiondirection is taken greater than a length of the bending members 26 b inthe width direction. A cross-sectional surface of each bending member 26b along the width direction spreads out at the bottom with respect to alateral face of the bending unit 26. One side of the bending member 26 bon an edge of the width direction is perpendicular to the foundationmember 26 a, forming a right-angled triangle along the transmissiondirection. Further, the cross-sectional surface along the widthdirection is similar to the right-angled triangle along the transmissiondirection and a surface area of the cross-sectional surface along thewidth direction is reduced. In other words, the bending members 26 bproject from both edges of the bending unit 26 in a stacking directionof the imaging target media P and an amount of projection goes ondecreasing along the transmission direction.

Moreover, each bending member 26 b according to the first embodimentincludes a guiding unit 27. The guiding units 27 regulate a movement ofthe imaging target media P, which are transmitted by the transmittingroller 14, in the width direction. Each guiding unit 27 is integratedwith the bending member 26 b on both sides of the width direction. Theguiding units 27 are in the form of rectangular boards and that are seton the bending members 26 b with a board thickness in the widthdirection. A tip of each guiding unit 27 along the stacking direction ofthe imaging target media P occupies the same position as that of a tipof each bending member 26 b at the rear end of the transmissiondirection. Due to this, in a portion of the tray 12 in which the imagingtarget media P are stacked, from the rear end to the front of thetransmission direction, an area of the bending members 26 b facing theimaging target media P goes on reducing with an increase in an area ofthe guiding units 27 facing the imaging target media P. Accordingly, themutually opposing guiding units 27 regulate the movement of the imagingtarget media P, which are transmitted by the transmitting roller, in thewidth direction.

The transmitting roller 14 transmits the imaging target media P stackedin the tray 12 to imaging units 28. As shown in FIG. 4, the transmittingroller 14 touches a transportation imaging-target medium Pc among theimaging target media P stacked in the tray 12. The motor 18 rotates thetransmitting roller 14 and the transmitting roller 14 transmits thetouched transportation imaging-target medium Pc to the imaging units 28.

Among the imaging target media P stacked in the tray 12, the separatingroller 16 prevents transmission of the separation imaging-target mediumPs that is not to be transported to the imaging units 28. The separatingroller 16 touches the separation imaging-target medium PS, which is notto be transported, among the imaging target media P stacked in the tray12. Further, the separating roller 16 separates the touched separationimaging-target medium Ps from the transportation imaging-target mediumPc by moving the separation imaging-target medium Ps in a directionopposite to the transportation imaging-target medium Pc, which istransported to the imaging units 28 by the transmitting roller 14, thuspreventing transmission of the separation imaging-target medium Ps tothe imaging units 28. To explain further, the transmitting roller 14 ispositioned opposite to the separating roller 16. A torque limiter (notshown) is attached to a rotating shaft of the separating roller 16. Whenthe imaging target media P are transmitted by the transmitting roller 14to the imaging units 28, the separating roller 16 rotates with a slowrotational velocity than the rotational velocity of the transmittingroller 14. Consequently, the separating roller 16 moves the separationimaging-target medium Ps in the direction opposite to the transportationimaging-target medium Pc and prevents transmission of the separationimaging-target medium Ps to the imaging units 28.

The motor 18 rotatably drives the transmitting roller 14. The motor 18,which is coupled to the rotational shaft of the transmitting roller 14,receives a power supply from the control circuit 24 and rotates thetransmitting roller 14.

The transporting rollers 20 transport the transportation imaging-targetmedium Pc to an imaging position of the imaging target medium P formedby the imaging units 28. The transporting rollers 20 are coupled to amotor 29 connected to the control circuit 24. The transporting rollers20 rotate due to a driving force of the motor 29 to which power issupplied from the control circuit 24, touch the transportationimaging-target medium Pc transmitted by the transmitting roller 14, andtransport the touched transportation imaging-target medium Pc to theimaging position of the imaging target medium P formed by the imagingunits 28.

The detecting sensors 22 detect whether the imaging target media Ptransmitted by the transmitting roller 14 are only the transportationimaging-target media Pc. The detecting sensors 22 are set between thetransmitting roller 14 and the transporting rollers 20. As shown inFIGS. 5A and 5B, the detecting sensors 22 are, for example, ultrasonicsensors. In the first embodiment, a pair of the detecting sensors 22 isarranged sandwiching a transportation path, which is a movement locus ofthe imaging target medium P, and the detecting sensors 22 are placedopposite to each other along a thickness direction of the imaging targetmedium P transmitted by the transmitting roller 14. Further, in thefirst embodiment, the detecting sensors 22 throw ultrasonic waves on theimaging target medium P and detect an amount of variation of theultrasonic waves that undergo variation when passing through the imagingtarget medium P.

The control circuit 24 controls rotation of the transmitting roller 14via the motor 18. The control circuit 24 is connected to the motor 18.When the detecting sensors 22 detect that the imaging target media P arenot only the transportation imaging-target media Pc, the control circuit24 stops the power supply to the motor 18 and stops rotation of thetransmitting roller 14 via the motor 18. In the first embodiment, athreshold value of an output level of the detecting sensors 22 is setbetween the output level of the detecting sensors 22 when the detectingsensors 22 detect only one imaging target medium P and the output levelof the detecting sensors 22 when the detecting sensors 22 detect morethan two imaging target media P. When the output level of the detectingsensors 22 is less than the threshold value, the control circuit 24determines that the imaging target media P detected by the detectingsensors 22 are not only the transportation imaging-target media Pc. Inother words, when the output level of the detecting sensors 22 is lessthan the threshold value, the control circuit 24 determines that theimaging target media P detected by the detecting sensors 22 are morethan two. Further, when it is determined that the imaging target media Pdetected by the detecting sensors 22 are more than two, the controlcircuit 24 stops the power supply to the motor 18 and stops rotation ofthe transmitting roller 14.

When a command to start scanning of the imaging target media P is inputby a scan switch (not shown), the control circuit 24 supplies power toeach of the motor 18 and the motor 29, and rotates the transmittingroller 14 and the transporting rollers 20, respectively. Further, when acommand to end scanning of the imaging target media P is input by a scanstop switch (not shown), the control circuit 24 stops the power supplyto at least the motor 18 and stops rotation of at least the transmittingroller 14. In the first embodiment, when the command to end scanning ofthe imaging target media P is input, the control circuit 24 stops thepower supply to the motor 18 and the motor 29, and stops rotation of thetransmitting roller 14 driven by the motor 18 and also stops rotation ofthe transporting rollers 20 driven by the motor 29.

As shown in FIG. 1, a pair of discharging rollers 30 is arrangeddownstream in the transmission direction of the imaging target media Pahead of the imaging units 28 and the discharging rollers 30 arearranged opposite to each other sandwiching the transportation path,which is the movement locus of the imaging target medium P.

Sheets, overhead projector (OHP) sheets etc. can be used as the imagingtarget media P mentioned above.

Operations of the sheet feeding device 10 according to the firstembodiment of the present invention are explained below.

FIG. 6 is a flowchart of the operations of the sheet feeding device 10.

When the imaging target media P are stacked in the tray 12 of the sheetfeeding device 10 and if the scan switch (not shown) of the imagescanner is pressed, the command to start scanning of the imaging targetmedia P is input to the control circuit 24, and power is supplied to themotor 18 and the motor 29 from the control circuit 24 (Yes at StepS100). Due to this, the transmitting roller 14 and the transportingrollers 20 are rotated (Step S102). Thus, the image scanner to which thesheet feeding device 10 is applied starts a process of scanning theimaging target media P. Next, the bending unit 26 of the tray 12 bendsthe imaging target media P stacked in the tray 12 in the direction thatintersects the transmission direction of the imaging target media P bythe transmitting roller 14, that is, the bending unit 26 bends theimaging target media P in the width direction that is orthogonal to thetransmission direction.

Among the imaging target media P stacked in the tray 12, when a singletransportation imaging-target medium Pc is not bound to the separationimaging-target medium Ps by using the binding member such as a stapler,the transportation imaging-target medium Pc touches the transmittingroller 14 that receives a rotational driving force of the motor 18 andthe transportation imaging-target medium Pc is transported to theimaging units 28 due to the rotational force of the transmitting roller14. On the other hand, when the separation imaging-target medium Pstouches the separating roller 16, a frictional force is generatedbetween the separation imaging-target medium Ps and the separatingroller 16. Due to this, the separation imaging-target medium Ps isseparated from the transportation imaging-target medium Pc by moving theseparation imaging-target medium Ps in the direction opposite to thetransportation imaging-target medium Pc, which is transported to theimaging units 28 by the transmitting roller 14, and transmission of theseparation imaging-target medium Ps to the imaging units 28 isprevented. Consequently, only the transportation imaging-target mediumPc, which is to be transmitted, is transmitted by the transmittingroller 14.

Alternatively, when the separation imaging-target medium Ps is notseparated by the separating roller 16 from the transportationimaging-target medium Pc transmitted to the imaging units 28 by thetransmitting roller 14, or when the separation imaging-target medium Psand the transportation imaging-target medium Pc, which is transmitted tothe imaging units 28 by the transmitting roller 14, are bound togetherat the front end of the transmission direction by using the bindingmember such as a stapler, the transportation imaging-target medium Pcand the separation imaging-target medium Ps are transmitted together tothe imaging units 28 due to the rotational force of the transmittingroller 14, which receives the rotational driving force of the motor 18.For example, even if the separation imaging-target medium Ps and thetransportation imaging-target medium Pc, which is transmitted to theimaging units 28 by the transmitting roller 14, are bound together atthe rear end of the transmission direction by using the binding membersuch as a stapler, the separation imaging-target medium Ps is benttogether with the transportation imaging-target medium Pc by the bendingunit 26 along the width direction to strengthen rigidity in thetransmission direction as described above. More specifically, becausethe rigidity in the transmission direction is increased than therigidity before bending, the separation imaging-target medium Ps, whentouches the separating roller 16, does not bend in the transmissiondirection. Consequently, the separation imaging-target medium Ps boundtogether with the transportation imaging-target medium Pc, which istransmitted to the imaging units 28 by the transmitting roller 14, atthe rear end of the transmission direction by using the binding membersuch as a stapler is transmitted to the imaging units 28 along with thetransportation imaging-target medium Pc due to the rotational force ofthe transmitting roller 14. In other words, when a plurality of imagingtarget media P, which are bound together at the rear end of thetransmission direction by using the binding member, are transmitted bythe transmitting roller 14 that receives the rotational driving force ofthe motor 18, a plurality of imaging target media P are transportedtogether to the imaging units 28.

Subsequently, the imaging target medium P, which is transmitted by thetransmitting roller 14 to the imaging position formed by the imagingunits 28, is detected by the detecting sensors 22 (Step S104).Specifically, the ultrasonic waves are thrown on the imaging targetmedium P and the amount of variation of the ultrasonic waves thatundergo variation when passing through the imaging target medium P isdetected by the detecting sensors 22.

When the output level of the detecting sensors 22 is greater than thethreshold value, the control circuit 24 determines that only thetransportation imaging-target medium Pc is positioned at a detectionposition of the imaging target medium P in the detecting sensors 22.When the control circuit 24 determines that only the transportationimaging-target medium Pc is positioned at the detection position of theimaging target medium P in the detecting sensors 22, in other words,when the imaging target medium P detected by the detecting sensors 22 isonly the transportation imaging-target medium Pc, the transportationimaging-target medium Pc is transported by the transporting rollers 20to the imaging position formed by the imaging units 28 (Yes at StepS104), images of the transportation imaging-target medium Pc are takenby the imaging units 28 (Step S106), and image data corresponding to thetransportation imaging-target medium Pc is generated using an image-datagenerating circuit (not shown) of the image scanner (Step S108). If thescan stop switch (not shown) of the image scanner is pressed, thecommand to end scanning of the imaging target media P is input to thecontrol circuit 24 (Yes at Step S110) and the power supply to the motor18 and the motor 29 from the control circuit 24 is stopped. Due to this,rotation of the transmitting roller 14 and the transporting rollers 20is stopped, and the image scanner to which the sheet feeding device 10is applied ends the process of scanning the imaging target media P (StepS112). If the command to end scanning of the imaging target media P isnot input to the control circuit 24 (No at Step S110), while the controlcircuit 24 determines whether the imaging target medium P detected bythe detecting sensors 22 is only the transportation imaging-targetmedium Pc, images of the transportation imaging-target medium Pc aretaken by the imaging units 28 and the image data corresponding to thetransportation imaging-target medium Pc is generated again.

On the other hand, when the output level of the detecting sensors 22 isless than the threshold value, the control circuit 24 determines thatthe imaging target media P detected by the detecting sensors 22 are notonly the transportation imaging-target media Pc, in other words, thecontrol circuit 24 detects a so-called bulk-transmission in which morethan two imaging target media P are transmitted. When the controlcircuit 24 determines the bulk-transmission of the imaging target mediaP, in other words, when it is detected that a plurality of imagingtarget media P are transmitted to the transporting rollers 20, the powersupply to the motor 18 and the motor 29 from the control circuit 24 isstopped (No at Step S104). Consequently, rotation of the transmittingroller 14 and the transporting rollers 20 is stopped. Due to this,transmission of the transportation imaging-target media Pc by thetransmitting roller 14 and transportation of the transportationimaging-target media Pc by the transporting rollers 20 are stopped.Therefore, a plurality of imaging target media P are not transported bythe transporting rollers 20 to the imaging position formed by theimaging units 28, however, transportation of the imaging target media Pis stopped just before the transporting rollers 20 and the image scannerto which the sheet feeding device 10 is applied discontinues the processof scanning the imaging target media P (Step S114). Subsequently, byusing an informing unit such as a display screen or a display lamp (notshown) that informs the user of an abnormal condition of the imagescanner, it is informed to a user that the scanning process isdiscontinued.

As mentioned earlier, although a dedicated sensor that detects bendingof the separation imaging-target medium Ps is not set, and even if aplurality of sheet-type imaging target media P are bound together at therear end of the transmission direction by using the binding member,transportation of the imaging target media P, which are bound together,to the imaging position formed by the imaging units 28 can besuppressed. In other words, the bulk-transportation of a plurality ofsheet-type imaging target media P to the imaging position formed by theimaging units 28 can be suppressed.

In the sheet feeding device 10 of the first embodiment, by using asimple structure of the bending unit 26 that includes the foundationmember 26 a and a pair of the bending members 26 b, the rigidity of theimaging target media P, which are stacked in the tray 12, in thetransmission direction can be increased.

In the bending unit 26, because the degree of bending of the imagingtarget media P, which are stacked in the tray 12, decreases from therear end to the front end of the transmission direction, the imagingtarget media P can be smoothly transferred to the transmitting roller 14and the separating roller 16.

When the imaging target media P, which are stacked in the tray 12, aretransferred to the transmitting roller 14 and the separating roller 16,the movement of the imaging target media P in the width direction isregulated by the guiding units 27 of the bending unit 26. Accordingly, adisplacement of the imaging target media P, which are bent by thebending unit 26, in the width direction can be prevented.

As mentioned earlier, a plurality of sheet-type imaging target media P,which are bound together at the rear end of the transmission direction,are transmitted directly from the tray due to the rotational force ofthe transmitting roller 14. Therefore, rupture of the imaging targetmedia P due to the binding component of the imaging media P that arebound together by using the binding member, jam of the imaging targetmedia P occurring between the transmitting roller 14 and the separatingroller 16 can be suppressed.

In the first embodiment, when the imaging target media P detected by thedetecting sensors 22 are not only the transportation imaging-targetmedia Pc, the control circuit 24 stops the power supply to the motor 18and the motor 29, and stops rotation of the transmitting roller 14 andthe transporting rollers 20. However, the present invention is not to bethus limited. In the present invention, the sheet feeding device can bestructured such that when the imaging target media P detected by thedetecting sensors 22 are not only the transportation imaging-targetmedia Pc, a rotatably driving unit stops rotation of at least thetransmitting roller 14, for example, the control circuit 24 stops thepower supply to the motor 18 and stops rotation of the transmittingroller 14.

In the first embodiment, although the separating roller 16 is applied asa separating unit, the present invention is not to be thus limited. Inthe present invention, for example, a separating board can be applied asa separating unit and can be arranged opposite to the transmittingroller 14. When the separating board touches the separationimaging-target medium Ps, a frictional force in a direction opposite tothe transmission direction can be exerted on the separationimaging-target medium Ps and the separation imaging-target medium Ps canbe separated from the transportation imaging-target medium Pc by movingthe separation imaging-target medium Ps in the direction opposite to thetransportation imaging-target medium Pc.

A sheet feeding device according to a second embodiment of the presentinvention is explained below. FIGS. 7A and 7B are perspective views of abending unit of a tray of the sheet feeding device according to thesecond embodiment. Structural components that are similar to the firstembodiment described above carry identical reference numerals and aredundant explanation thereof is omitted.

As shown in FIG. 7A, in the second embodiment, the tray 12 isrectangular in shape. The tray 12 is formed of the foundation member 26a arranged in a central portion of the width direction and a pair of thebending members 26 b arranged on both edges of the width direction.

A surface of the foundation member 26 a facing the imaging target mediumP is an isosceles trapezoidal board having a wide base along thetransmission direction. Alternatively, the surface of the foundationmember 26 a facing the imaging target medium P can be an isoscelestriangular board having a wide base along the transmission direction.

A surface of each bending member 26 b facing the imaging target medium Pis a right-angled triangular board and a dimension of each bendingmember 26 b in the width direction goes on decreasing along thetransmission direction. Each bending member 26 b is attached to thefoundation member 26 a using hinges. As shown in FIG. 7B, each bendingmember 26 b is supported on both edges of the foundation member 26 a inthe width direction by the hinges such that each bending member 26 b canbe raised above the foundation member 26 a. When raised above thefoundation member 26 a, each bending member 26 b projects in a stackingdirection of the imaging target media P and an amount of projection goeson decreasing along the transmission direction.

In the sheet feeding device 10 according to the second embodiment, apair of the bending members 26 b is supported by the hinges such thateach bending member 26 b can be raised above the foundation member 26 a.Due to this, the user can select whether to bend the imaging targetmedia P stacked in the tray 12. The remaining structural components inthe second embodiment are the same as mentioned in the first embodiment.

A sheet feeding device according to a third embodiment of the presentinvention is explained below. FIG. 8 is a perspective view of a bendingunit of a tray of the sheet feeding device according to the thirdembodiment. The structural components that are similar to the first andthe second embodiments described above carry identical referencenumerals and a redundant explanation thereof is omitted.

In the third embodiment, at least one of the two bending members 26 b ofthe bending unit 26 described in the first embodiment is supported suchthat the bending member 26 b can slide over the foundation member 26 aalong the width direction. More specifically, as shown in FIG. 8, boththe bending members 26 b are supported such that the bending members 26b can slide over the foundation member 26 a along the width direction.

To explain further, each bending member 26 b includes a rectangularboard-shaped sliding unit in addition to the guiding unit 27 describedin the first embodiment. Each sliding unit is thick in the stackingdirection of the imaging target medium P and that is slidably mounted onrail members (not shown) that are fixed to the foundation member 26 aalong the width direction. Due to this, each sliding unit slides alongthe rail members in the width direction, thus enabling the bendingmembers 26 b to slide over the foundation member 26 a along the widthdirection. In the third embodiment, both the bending members 26 b assumea centerline in the width-direction of the foundation member 26 a as acenter and slide over the foundation member 26 a along the widthdirection in conjunction with each other. If only one of the two bendingmembers 26 b is slidably supported on the foundation member 26 a, one ofthe two bending members 26 b can be fixed to the foundation member 26 a,while the other can be supported such that the other bending member 26 bcan slide along the rail members fixed to the foundation member 26 aalong the width direction.

In the sheet feeding device 10 according to the third embodiment, atleast one of the two bending members 26 b, or both the bending members26 b are supported such that the bending members 26 b can slide alongthe rail members over the foundation member 26 a in the width direction.Due to this, spacing between the bending members 26 b can be adjustedaccording to a size of the imaging target medium P in the widthdirection. Consequently, the imaging target medium P can be bentaccording to the size. The remaining structural components in thepresent embodiment are the same as that mentioned in the firstembodiment.

A sheet feeding device according to a fourth embodiment of the presentinvention is explained below. FIG. 9 is a perspective view of a bendingunit of a tray of the sheet feeding device according to the fourthembodiment. The sheet feeding device 10 according to the fourthembodiment includes, in addition to any one of the first to the thirdembodiments, a pressing member 34 that presses the imaging target mediaP stacked in the tray 12 towards the tray 12 and bends the imagingtarget media P. The structural components that are similar to the first,second, and third embodiments described above carry identical referencenumerals and a redundant explanation thereof is omitted.

The sheet feeding device 10 according to the fourth embodiment includesthe pressing member 34, which is placed opposite to the tray 12 andincludes a pressing and bending unit 34 a and a supporting unit 34 b.

The pressing and bending unit 34 a presses the imaging target media Pstacked in the tray towards the tray 12 and bends the imaging targetmedia P according to a shape of the bending unit 26. The pressing andbending unit 34 a is spherical in shape. Alternatively, the pressing andbending unit 34 a can be formed as a block as shown in FIG. 10.

The supporting unit 34 b, which supports the pressing and bending unit34 a at the front end, is in the form of a long rod. In such asupporting unit 34 b, a proximal portion of the supporting unit 34 b onan opposite side of the pressing and bending unit 34 a is fixed to achassis of the image scanner to which the sheet feeding device 10 isapplied.

As shown in FIG. 11, when a thick imaging target medium P is stacked inthe tray 12, in other words, when the imaging target medium P havingmore rigidity than a thin imaging target medium P is stacked in the tray12, bending of the imaging target medium P is suppressed. However, asshown in FIG. 9, in the sheet feeding device 10 according to the fourthembodiment, by pressing the imaging target medium P towards the tray 12using the pressing and bending unit 34 a of the pressing member 34, theimaging target medium P is bent according to the shape of the bendingunit 26. Consequently, the rigidity of the imaging target medium P inthe transportation direction can be further increased.

In the fourth embodiment, when the proximal portion of the supportingunit 34 b on the opposite side of the pressing and bending unit 34 a isfixed, the supporting unit 34 b can be structured to bend almost in thestacking direction of the imaging target medium P.

A sheet feeding device according to a fifth embodiment of the presentinvention is explained below. FIG. 12 is a typical sectional view of anoutline of the sheet feeding device according to the fifth embodiment.In the sheet feeding device 10 according to the fifth embodiment, theproximal portion of the supporting unit 34 b on the opposite side of thepressing and bending unit 34 a is assumed as a center and the pressingmember 34 described in the fourth embodiment can oscillate about thecenter. Further, structural components that are similar to the fourthembodiment described above carry identical reference numerals and aredundant explanation thereof is omitted.

Depending on a reaction force due to a pressing force exerted by thepressing and bending unit 34 a on the imaging target medium P, thepressing and bending unit 34 a of the pressing member 34 according tothe fifth embodiment can oscillate almost in the stacking direction ofthe imaging target medium P about the center, that is, the proximalportion of the supporting unit 34 b. In the supporting unit 34 b, tobias the pressing and bending unit 34 a towards the tray 12, theproximal portion on the opposite side of the pressing and bending unit34 a can be biased using a biasing member such as a leaf spring.

In the sheet feeding device 10 according to the fifth embodiment,depending on the reaction force due to the pressing force exerted by thepressing and bending unit 34 a on the imaging target medium P, thepressing member 34 oscillates about the center, that is, the proximalportion of the supporting unit 34 b on the opposite side of the pressingand bending unit 34 a. Due to this, a load exerted by the pressing andbending unit 34 a on the imaging target medium P can be reduced ascompared to the load exerted by the pressing member 34 in which theproximal portion of the supporting unit 34 b on the opposite side of thepressing and bending unit 34 a does not oscillate (the pressing member34 according to the fourth embodiment described above).

A sheet feeding device according to a sixth embodiment of the presentinvention is explained below. FIG. 13 is a typical sectional view of anoutline of the sheet feeding device according to the sixth embodiment.In the sheet feeding device 10 according to the sixth embodiment, thepressing and bending unit 34 a of the pressing member 34 according tothe fourth embodiment is in the form of a sliding roller, and thefrictional force between the pressing and bending unit 34 a and theimaging medium P is reduced. Further, structural components that aresimilar to the fourth embodiment described above carry identicalreference numerals and a redundant explanation thereof is omitted.

In the sheet feeding device 10 according to the sixth embodiment, thepressing and bending unit 34 a of the pressing member 34 is in the formof the sliding roller that is supported by the supporting unit 34 ballowing free rotation of the pressing and bending unit 34 a. Thesliding roller according to the sixth embodiment slides by rotating withrespect to the pressed imaging target medium P along with the movementof the pressed imaging target medium P in the transmission direction.

In the sheet feeding device 10 according to the sixth embodiment, whenthe imaging target medium P, which is pressed by the pressing andbending unit 34 a of the pressing member 34, moves along thetransmission direction, the pressing and bending unit 34 a slides byrotating with respect to the imaging target medium P. Therefore,increase in the frictional force arising between the pressing andbending unit 34 a and the imaging target medium P can be suppressedwithout reducing the pressing force exerted on the imaging target mediumP by the pressing and bending unit 34 a of the pressing member 34.

According to an embodiment of the present invention, imaging targetmedia stacked in a tray are bent by using a bending unit of the tray ina direction that crosses a transmission direction of the imaging targetmedia by a transmitting roller, for example, in a width direction thatis orthogonal to the transmission direction. Rigidity of the imagingtarget media, which are stacked in the tray, along the transmissiondirection is increased than the rigidity of the imaging target mediabefore bending. Consequently, when a transportation imaging-targetmedium and a separation imaging-target medium are bound together using abinding member such as a stapler, and when the transportationimaging-target medium is transmitted to imaging units by thetransmitting roller, the separation imaging-target medium is transmittedto the imaging units along with the transportation imaging-target mediumwithout bending in the transmission direction. In other words, when aplurality of imaging target media bound together by the binding memberare transmitted by the transmitting roller, a plurality of imagingtarget media are transmitted together to the imaging units. Further,detecting sensors detect that the imaging target media transmitted totransporting rollers are not only the transportation imaging-targetmedia, in other words, the detecting sensors detect that a plurality ofimaging target media are transmitted to the transporting roller, and acontrolling unit stops rotation of at least the transmitting roller.Consequently, a plurality of imaging target media are not transported bythe transporting rollers to an imaging position formed by the imagingunits and transportation is stopped just before the transporting roller.Thus, even though a dedicated sensor that detects bending of theseparation imaging-target media is not set, when a plurality of imagingtarget media are bound together by the binding member, transportation ofa plurality of imaging target media, which are bound together, to theimaging position formed by the imaging units can be suppressed.

According to an embodiment of the present invention, a degree of bendingof the imaging target media stacked in the tray reduces from a rear endto a front end of the transmission direction. Therefore, the imagingtarget media can be smoothly transferred to the transmitting roller anda separating unit.

According to an embodiment of the present invention, the bending unitincludes a foundation member and a pair of bending members. Due to sucha simple structure of the bending unit, the rigidity of the imagingtarget media, which are stacked in the tray, in the transmissiondirection can be increased.

According to an embodiment of the present invention, a pair of thebending members is supported such that the bending members can be raisedabove the foundation member. Therefore, a user can select whether tobend the imaging target media.

According to an embodiment of the present invention, at least one of thetwo bending members is supported such that the bending member can slideover the foundation member along the width direction. Therefore, spacingbetween the two bending members can be adjusted according to a size ofthe imaging target media in the width direction. Due to this, theimaging target media can be bent according to the size.

According to an embodiment of the present invention, when the imagingtarget media stacked in the tray are transferred to the transmittingroller and the separating unit, the movement of the imaging targetmedium along the width direction is regulated using guiding units.Consequently, a displacement of the imaging target media, which are bentby the bending unit, in the width direction can be prevented.

According to an embodiment of the present invention, when thick imagingtarget media are stacked in the tray, in other words, when the imagingtarget media having more rigidity than thin imaging target media arestacked in the tray, bending of the imaging target media is suppressed.However, because the imaging target media are bent towards the tray bythe pressing and bending unit of the bending member, the imaging targetmedia are bent according to a shape of the bending unit. Consequently,the rigidity of the imaging target media in the transmission directioncan be further increased.

According to an embodiment of the present invention, depending on areaction force due to a pressing force exerted by the pressing andbending unit on the imaging target media, the pressing member oscillatesconsidering a proximal portion of the supporting unit as a center. Dueto this, load added to the imaging target media by the pressing andbending unit can be reduced as compared to the bending member in whichthe proximal portion of the supporting member does not oscillate.

According to an embodiment of the present invention, when the imagingtarget media, which are pressed by the pressing and bending unit of thebending member, move along the transmission direction, the pressing andbending unit slides with respect to the imaging target media. Therefore,increase in a frictional force arising between the pressing and bendingunit and the imaging target medium can be suppressed without reducingthe pressing force on the imaging target media exerted by the pressingand bending unit.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

1. A sheet feeding device comprising: a tray in which sheet-type imagingtarget media are stacked; a transmitting roller that rotates andtransmits, upon touching a single imaging target medium that is to betransported among the stacked imaging target media, the touchedtransportation imaging-target medium to an imaging unit; a separatingunit that touches, among the stacked imaging target media, a separationimaging-target medium that is not to be transported, separates theseparation imaging-target medium by moving the separation imaging-targetmedium in a direction opposite to the transportation imaging-targetmedium that is transmitted to the imaging unit by the transmittingroller, and prevents transmission of the separation imaging-targetmedium to the imaging unit; a rotatably driving unit that rotatablydrives the transmitting roller; a transporting roller that rotates andtransports, upon touching the transportation imaging-target mediumtransmitted by the transmitting roller, the touched transportationimaging-target medium to an imaging position of the imaging targetmedium formed by the imaging unit; a detecting sensor that is setbetween the transmitting roller and the transporting roller and thatdetects whether the imaging target media transmitted by the transmittingroller are only the transportation imaging-target media; and acontrolling unit that stops, upon determining that the detected imagingtarget media include the imaging target media other than thetransportation imaging-target media, rotation of at least thetransmitting roller via the rotatably driving unit, wherein the trayincludes a bending unit that bends the stacked imaging target media froma rear to a front end of a transmission direction, in a direction thatintersects the transmission direction of the imaging target media by thetransmitting roller and reduces a degree of bending of the imagingtarget media from the rear end to the front end of the transmissiondirection.
 2. The sheet feeding device according to claim 1, wherein thebending unit includes a foundation member facing the stacked imagingtarget media and a pair of bending members mounted on the foundationmember on both edges of a width direction that is orthogonal to thetransmission direction, and the bending members project in a stackingdirection of the imaging target media and an amount of projectionreduces along the transmission direction.
 3. The sheet feeding deviceaccording to claim 2, wherein the bending members are supported on bothedges of the width direction of the foundation member such that thebending members can be raised above the foundation member, and thebending members project, upon raising, from lateral surfaces of thefoundation member in a stacking direction of the imaging target mediaand the amount of projection reduces along the transmission direction.4. The sheet feeding device according to claim 2, wherein at least oneof the two bending members is supported such that the bending member canslide over the foundation member along the width direction.
 5. The sheetfeeding device according to claim 2, wherein the bending members includemutually opposing guiding units that regulate a movement of the imagingtarget media transmitted by the transmitting roller, in the widthdirection.
 6. The sheet feeding device according to claim 1, furthercomprising: a pressing member arranged facing the tray and that includesa bending and pressing member that presses the imaging target mediastacked in the tray towards the tray and bends the imaging target mediaaccording to a shape of the bending unit, and a supporting unit thatsupports the bending and pressing unit at the front end.
 7. The sheetfeeding device according to claim 6, wherein, depending on a reactionforce due to a pressing force exerted by the pressing and bending uniton the imaging target media, the pressing and bending unit of thepressing member can oscillate in a direction away from the tray with aproximal portion of the supporting unit as a center.
 8. The sheetfeeding device according to claim 6, wherein the pressing and bendingunit includes a sliding roller supported by the supporting unit allowingfree rotation, and the pressing and bending unit slides with respect tothe pressed imaging target media along with a movement of the pressedimaging target media in the transmission direction.